Machine for drawing thin-walled metal tubes.



H. VON FORSTER.

MACHINE FOR DRAWING-THIN WALLED METAL TUBES.

APPLICATION FILED AUG|18I1915I Patented Nov. 14, 1916.

Jaye/afar, l alimiziz #2519161 HERMANN voN FORSTER, OF FRANKFORT-ON-THE-MAIN, GERMANY.

MA CHINE DRAWING THIN-WALLED METAL TUBES.

Specification of Letters Patent.

Patented Nov. 14, 1916.

' Application filed August 18, 1915. Serial No. 46,178.

7b all whom it may concern Be it known that I, HERMANN VON Fons- TER, subject of the King of Prussia, residing at Roseggerstrasse 32. Frankfort-on-the- Main, Germany, have invented certain new and useful Improvements in Machines for Drawing Thin-Valled Metal Tubes, of which the following is a specification.

My invention relates to the manufacture of thin-walled metal tubes and its particular object is a machine for drawing such tubes in a cold state in a great number of succeeding passeswithout annealing the tubes between the passes. This mode of manufacture of thin-walled tubes offers the advantage of a great economy of time, much time being lost in the old methods by the annealing operations, so that it took several days to make a tube whereas with the machine according to this invention a raw blank is converted into a thin-walled tube within afew minutes. To-this end a great number of dies (from 20 to 30 and even more) are arranged in line at one end of the machine. These dies are passed in close succession over the'blank causing it to be drawn out substantially uniformlyin each pass, gripping devices or the like being provided on the machine for gripping the dies or the die holders and for guiding them over the blank.

In view of the rapid succession of passes required for finishing the thin tubes in the shortest possible time provision must be made for a very'eifective lubrication, and means must be provided forneutralizing the heat locally generated in those places where the drawing tools are working. To this end the entire upper part of the machine is preferably constructed so as to form a trough filled with lubricant, the blank as well as the dies being immersed in the liquid lubricant altogether and a very effective equalization of temperature all over the blank being obtained besides the lubrication.

Each metal allowing to be drawn out but at a certain temperature, and each lubricant presenting the greatest lubricating power at a certain temperature also, the machine according to this invention is further provided with means. preferably arranged below the trough containing-the lubricant, for heating or cooling and for impartin to the blank, the dies and thelubric'ant t e temperature most suitable for the drawing procedure.

Preferably the composition of the lubricant should be such as to present the highest pos- 7 sible lubricating power at the temperature which is the most favorable for drawing the respective metal. The trough may be. re placed by other suitable devices such as s raying or rinsing devices for distributing t e lubricant.

In the drawings. accompanying this specification the preferred form of a machine according to my invention is represented, Figure 1 being a vertical longitude nal section, Fig. 2 a detail, in section, Fig. 3 a plan view.

aare standards carrying the trough b inclosing the drawing mechanism. t

o is a heating device arranged below the trough. T

(Z is a heating tube for passing a hot liquid or steam through the trough. I

e is the mandrel rigidly fixed to the trough at one end by a nut f while the other end lies loosely on a support g.

his the hollow blank placed on the mandrel. The fixed end of the mandrel which is reduced in thickness as usual is of such diameter as to allow the smallest die required in the drawing operation to be drawn over it. The dies z are placed in a line upon the reduced end of the mandrel within the trough. A gliding piece is carrying grip I pers Z is movably arranged within the trough and is linked to the ends-of connecting rods m fastened, at their other ends, to a glid-' ing piece 1' movable on guides ,outside the trough. A pair of slotted oscillating levers p linked to a horizontal pivot below said gliding piece r embrace a bolt 0 fastened to the connecting rods m near the gliding piece.

q is a crank disk rotated by suitable means and connected with said oscillating levers.

The operation of this machine is as follows: After the hollow blank h and all the dies-i have been placed upon the mandrel,

the foremost die is brought in contact with with a lubricant, such as for instance a soap solution to which Water-soluble oils have been added. The composition of the lubricant can be made such that it will have a good lubricating efiect even at temperatures between 100 and 200 degr. C. The temperature is controlled by aid of the heating or cooling devices provided for this end.

\Vhile the temperatures mentioned above are most favorable to the drawing capacity of certain brass alloys, other metals or alloys require different temperatures which can be ascertained in each case by a test. The kind of lubricant to be employed depends largely upon the Working temperature.

The crank and lever arrangement for driving the grippers may be replaced by othermeans, such as-a-rack and pinion gear or a piston moving in 'acylinder.

The machine may as well be employed for drawing work pieces other than ordinary tubes.

I claim 1. In a machine for drawing thin-walled tubes from a blank in a cold state, the combination-of a mandrel, a plurality of dies, and means for passing the dies separately in close succession over the mandrel.

2. In a machine for drawing thin-walled tubes from a blank in a cold state, the combination of a mandrel, aseries of dies arranged side by side at one end of the mandrel and adapted collectively to efi'ect the desired reduction of a blank supported by the mandrel, and means adapted'to move said dies one by one in close succession over the mandrel. 3. In a'machine for drawing thin-walled tubes from a blank in a cold'state, the combination of a mandrel, a plurality of dies, and grippers arranged to reciprocate longitudinally of the mandrel and adapted to suecessively engage the several dies, whereby the dies will be separately moved, in close succession, over the mandrel.

4. In a machine for drawing thin-walled tubes from a blank in a cold state, the combination of a mandrel, a plurality of dies, means for separately engaging the dies' and passing them in close succession over the mandrel, and means for maintaining a blank on the mandrel at substantially uniform temperature throughout the drawing operation.

5. In a machine for drawing thin-walled tubes from a blank in a cold state, the combination of a mandrel, a plurality of dies, means for passing the dies separately in close succession over the mandrel, and means for maintaining the mandrel, a blank thereon, and the operative die at the temperature at which the metal of the blank may be most readily drawn.

6. In a. machine for drawing thinqvalled tubes from a blank in a cold state, the combination of a mandrel, a plurality of dies, means for passing the dies separately in close succession over the mandrel, and a trough containing a suitable liquid lubricant which surrounds the mandrel, a blank thereon and the operative die.

In testimony whereof I affix my signature in presence of two witnesses.

HERMANN VON FORSTER.

\Vitnesses CARE GRUND,

H E. GARLsoN. 

